According to the data, a house that uses 1,000 kilowatt hours in a month would have paid $60.07 in 1998. The same amount would cost a resident $108.25 today.

The reason? Fixed rates.

The numbers

The Knoxville Utility Board charged customers just $5.32 in basic service fees from 1997 to 2003. The basic service fee is like a membership charge. It's the fee customers must pay each month for using KUB's electricity. Energy usage on top of that was $10.28 per thousand kilowatt hours.

In 2004, fixed rates went up by 77 cents and the energy usage cost went up by about $2.50 per thousand kilowatt hours.

In 2011, KUB decreased the energy usage cost by $2 and instead added $1.91 to its basic service fees. Every year since then basic service fees have increased by $1 and will increase by another $1.50 this year through 2020.

KUB spokesman Mike Bolin said the rate increases fund "Century II," an infrastructure replacement plan. "These rate increases of 1 percent or so per year have been about a plan to replace poles, substations, all the infrastructure to provide service."

Those increases may not end in 2020, however. KUB plans its annual budget three years out, and the last budget meeting was 2017.

And, Bolin said, the Century II maintenance program is an indefinite one. "Replacing your poles or something like that is almost like mowing your grass. It's going to keep going on."

Regarding the yearly increases, Bolin said KUB customers in focus groups said they would prefer to see fixed rate hikes dispersed over several years rather than in one big increase.

Stephen Smith of the Southern Alliance for Clean Energy said he would rather see rate increases applied to usage charges.

"Increasing the fixed fee has a number of very important negative financial consequences for customers, particularly low-income and lower-electricity users like senior citizens," he told the KUB board at a meeting Thursday.

"Different customers should be responsible for different costs of grid service based on how much of it they are using," he reasoned.

Increases on two sides

KUB gets the power it sells to customers from the Tennessee Valley Authority. To recover costs, KUB passes on 100 percent of TVA increases and decreases to customers.

In 1997 that was $44.47. For the last two years, it has been just under $80. Money to cover TVA costs will make up about 74 percent of the average electricity user's bill this year.

"Today, consumers can lower their bills through energy efficiency and even make some of their own energy," Larson wrote. "Power companies that don’t adapt and reinvent themselves won’t be able to ensure the safety, reliability and resilience consumers have come to expect."

Like KUB, TVA's stance seems to be that fixed rates should cover fixed costs.

Chief Financial Officer John Thomas said TVA's load and revenue have gone down in tandem. "That's the result predominantly of energy efficiency standards coming out of (the Department of Energy)."

Cass said the company is well-positioned to absorb declining load growth for now, but as more homes and businesses use less electricity, usage-based rate increases may not cover the costs of maintaining the grid for long.

Name-calling

Aside from utility bill increases, Smith said he is concerned the move toward fixed rates on residential customers may destroy the economics around energy efficiency and renewable energy.

Furthermore, environmental groups have said residential customers are trapped into the rate increases if they live in the inner Tennessee valley.

Certain residential distributors on the outer ends of the valley can choose to get their power from suppliers in bordering states. TVA spokesman Scott Brooks said Paducah Power was the last residential power distributor to leave TVA.

But, distributors in the inner valley have less choice. By federal law, no other power suppliers can use TV power lines to reach customers in the Valley, so distributors like KUB must get power from TVA because it is the only local supplier.

Disgruntled ratepayers lined up at a November TVA Board meeting to dispute the fixed-rate proposal, calling the company a de facto "monopoly," a term TVA does not abide.

At the meeting, TVA CEO Bill Johnson said the utility did not have a "monopoly" on power supply because its distributing utilities are free to seek another contract.

"Anyone can choose at any time to install solar or wind power, etc. and go 'off the grid' and create their own power," TVA's Brooks explained Thursday.

Customers with solar power who cannot store the energy must remain connected to the grid to receive power at night, however. So, Smith said, customers who invest in those solar systems or other forms of distributed generation still would be affected by fixed-rate increases.